To provide a masking device which causes no unevenness in coating vehicle wheels and reduces a cost in producing and managing masks.

A supporting stand 10, which supports a vehicle wheel 100, has a prop 11 and a vehicle wheel-supporting part 10a. The vehicle wheel-supporting part 10a includes a vehicle wheel-placing surface 12x, on which the vehicle wheel 100 is horizontally placed, and a positioning convex part 13 which projects upward from the vehicle wheel-placing surface 12x and positions the vehicle wheel 100 in the diameter direction. A mask 30 for a hub hole is separated from a plurality of masks 20 for nut seats. The mask 30 for the hub hole has a covering part 31, a grasping shaft part 32 which projects from the upper and under surfaces of the covering part 31 and a positioning shaft part 33. The positioning shaft part 33 is inserted into the positioning hole 16 of the supporting stand 10 to position the mask 30 for the hub hole in the diameter direction. The covering part 31 covers the reference cylinder surface 103x of the hub hole 103.